Aldehydes comprise important chemical compounds which are useful for a variety of purposes. One source of various aldehydes comprises alcohols, the aldehydes being prepared by the oxidative dehydrogenation of the corresponding alcohols. When this type of process is employed, the oxidative dehydrogenation has been effected in the presence of catalysts such as silver catalysts, platinum black, etc. The process conditions which have been used to effect this oxidation have been in the range of from about 450.degree. to about 550.degree. C. The by-products which have been obtained from this reaction usually include the corresponding acids, esters, ethers, etc., the amount of said by-products being dependent to some extent upon the operating parameters employed in the reaction. In addition to the oxidative dehydrogenation of the alcohols, other methods of obtaining aldehydes have included the direct oxidation of paraffins, the hydration of alkynes utilizing mercuric sulfate or ferric sulfate catalysts, etc.
As was previously set forth, aldehydes are important articles of commerce as, for example, acetaldehyde which is used in the preparation of acetic acid, acetic anhydride, chloral, as an intermediate for drugs, perfumes, photographic agents, in phenol and urea condensation products, etc. Likewise, propionaldehyde is used in the manufacture of polyvinyl acetals and other types of plastics, in the synthesis of rubber chemicals, as a disinfectant or preservative, etc; isovaleraldehyde is used in flavoring compounds, perfumes, pharmaceuticals, synthetic resins, rubber accelerators, etc.
In many instances when employing alcoholic feedstocks which are used in the oxidative dehydrogenation of alcohols to form aldehydes, it was necessary to employ alcohols which were anhydrous in nature. However, many processes such as fermentation obtain, as by-products, alcohols which are hydrous in nature and thus form an aqueous alcoholic solution. It has therefore become commercially attractive from an economic standpoint to effect the conversion of aqueous alcoholic solutions to chemical intermediates or other products such as fuels without requiring a stringent preparation process to remove the water before utilizing the alcoholic feedstock.
As will hereinafter be shown in greater detail, it has now been discovered that aqueous alcoholic solutions may be utilized as feedstocks to convert the alcohol to the corresponding aldehyde in an oxidation type reaction involving the use of a certain catalytic composition of matter without appreciably influencing the catalytic properties of said compositions of matter, especially in the retention of catalyst activity, selectivity, stability, etc.